textproduct: Quad Cities

KEY MESSAGES

- Increasingly warm and humid conditions will overspread the Midwest for much of the coming week. Right now there is a 33% probability that heat headlines may be needed for parts of the area through the middle of the week.

- The potential is there for active weather next week but that is dependent upon where the active storm track sets up around the edge of the heat dome.

SHORT TERM /THROUGH TONIGHT/

Issued at 152 AM CDT Sat Aug 29 2026

A strong LLJ in concert with an upper level disturbance is helping to support the convection in the Plains. However as the convection out runs the LLJ, it will slowly weaken with dissipation expected around mid-day or early afternoon.

Based on trends from the very short range models and their ensembles, areas north of Highway 30 and west of the Mississippi have the 'relatively better' chances for rain from mid to late morning. Much of the area will remain dry. Mid and high level clouds may suppress temperatures a little, especially north of I-80.

Tonight will start out dry. The LLJ will strengthen and be over the area tonight supplying moisture and some lift to generate another round of nocturnal showers/storms after midnight. However, there will not be an upper level disturbance to supply the stronger forcing. Thus any nocturnal convection that does develop will have low coverage (15-25%). Indeed output from the REFS depicts mainly isolated showers/storms with a few pockets of scattered coverage.

LONG TERM /SUNDAY THROUGH FRIDAY/

Issued at 152 AM CDT Sat Aug 29 2026

Sunday through Thursday Assessment...a certainty (>95%) of above normal temperatures.

Starting Sunday the heat dome slowly builds north into the area. Prime time for the worst of the heat and humidity looks to be in the Monday through Wednesday time period. Based on progged temperatures and dew points, heat indices around or exceeding 100 are possible with areas south of I-80 being favored. Record warm lows may be challenged on some days. Refer to the climate section for more specific information.

How warm it will get each day is dependent upon where the active storm track is located. Two scenarios are in play and each has a 50% chance of occurring: 1) the storm track runs from Minnesota into Wisconsin or 2) the storm track is over the area.

Right now the model consensus has low (20-30%) rain chances on a daily basis but favors areas north of I-80. This suggests that scenario 2 is the preferred scenario and suggests that any nocturnal incursion of convection may put a damper on daytime temperatures with more clouds. If correct, heat indices would only get to around 100.

Thursday night through Friday Assessment...low to medium (20-40%) confidence for rain with a late week cool front.

The global models vary but suggest a possible cool front arriving late in the week that may bring a brief respite from the heat and humidity.

There are timing differences between the various models but the model consensus suggests late Thursday night into Friday as a possible frontal passage. The rain chances are only 20-30% indicating the forcing with the front is not overly strong.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 635 AM CDT Sat Aug 29 2026

An area of rain with some isolated/embedded thunder over portions of central Iowa will continue to shift eastward through this morning into the early afternoon. DBQ/CID have the highest chances for showers/measurable rain with this wave (30-60%), with much lower chances to the south. Gusty southerly winds are expected this afternoon, reaching 20-25+ kts. Increasing southwesterly winds aloft (40-50 kts at 2000 ft AGL) tonight, with southerly winds at the surface, will result in a period of LLWS lasting into Sunday AM. Additional scattered showers and isolated storms may develop late tonight (mainly after 07Z/Sun.), but have low confidence on coverage so did not mention in TAFs with this update.

CLIMATE

Issued at 139 PM CDT Fri Aug 28 2026

Record Warm Low Temperatures:

August 31: KDBQ: 74/2000 KMLI: 75/2000

September 1: KDBQ: 73/1937 KMLI: 75/1913

September 2: KDBQ: 74/2011 KMLI: 77/1913

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.